For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInstallation Procedure
Drill 8 mm (5/16 in) for plug welding along the edges of the service
panel as noted from the original
panel.
Clean and prepare the attaching surfaces for welding.
Position the body lock pillar inner panel on the vehicle.
Verify the fit of the panel.
Clamp th ...
Brakes
This vehicle has front disc brakes and could have rear drum brakes or rear disc
brakes.
Disc brake pads have built-in wear indicators that make a high-pitched warning
sound when the brake pads are worn and new pads are needed.
The sound can come and go or be heard all the time the vehicle is m ...
Installation Procedure
Drill 8 mm (5/16 in) for plug welding along the edges of the service
panel as noted from the original panel.
Clean and prepare the attaching surfaces for welding.
Apply one-part windshield urethane adhesive as noted
from the original panel.
Position the roof ...